Masonry cutters are used to cut different types of masonry, for example, stone, cement, and concrete, such as concrete slabs and concrete blocks. Concrete is used in a variety of applications, for example, foundations, walls, pads, roads, curbstones, and in concrete slabs, such as are used to form sidewalks.
Sidewalks generally comprise a series of adjacent concrete slabs abutted along one edge. Adjacent slabs are generally aligned to present a level travelling surface to users of the sidewalk, such as pedestrians. Over time, adjacent sidewalk slabs may settle unevenly or may become raised by, for example, expansion and contraction of the underlying soil due to frost. When the abutting edge of a slab becomes raised as compared with an adjacent slab, it presents a trip hazard for users of the sidewalk. Although the definition of a trip hazard is somewhat subjective, it is generally considered that a raised edge of 1.5 cm or more presents a trip hazard to pedestrians. In addition to the safety risk to sidewalk users, sidewalk owners face liability from persons injured due to a fall and pay increased insurance premiums as a result. It is therefore desirable to eliminate trip hazards from sidewalks.
One way of removing trip hazards is to use a sidewalk lifter as disclosed in U.S. Pat. No. 4,962,913, issued Oct. 16, 1990. The sidewalk lifter comprises a rigid frame with cross members reaching over the sides of the section of sidewalk to be lifted. Winches on the cross members raise hooks attached to the section of sidewalk, thereby lifting it so that dirt may be added beneath the raised section. This apparatus is cumbersome to use and it is time consuming and labour intensive to repair sidewalks in this manner. Also, if there are pre-existing cracks in the sidewalk section, lifting the sidewalk section may exacerbate the cracks and potentially break the sidewalk section being lifted, which necessitates its replacement and could result in injury to workers.
Machines for cutting concrete are cumbersome, expensive and not particularly well adapted to the removal of trip hazards from sidewalks. U.S. Pat. No. 4,433,871, issued Feb. 28, 1984 shows a vehicle having two parallel booms with a bridge structure perpendicularly mounted thereto. The bridge structure has a rotary cutting saw carrier movably mounted thereon and four jacks, one at each corner of the bridge structure, that are deployed to stabilize the bridge structure while cutting. It is difficult to adjust the height of each jack independently without causing wobbling of the bridge structure due to uneven placement of the four jacks. This in turn makes it difficult to straddle a sidewalk slab with the bridge structure and difficult to adjust the saw to a desired cut angle. A cut can be made at an angle to the horizontal plane or to the vertical plane, but not at an angle to both planes at the same time, which further complicates adjusting the saw to the desired cut angle. This concrete cutter is impractical for removing trip hazards from sidewalks.
Another machine for cutting concrete is disclosed in U.S. Pat. No. 5,676,125, issued Oct. 14, 1997. A concrete saw is mounted at the end of an excavator boom. Although the saw can be maneuvered in many directions, the saw does not have the benefit of legs for straddling a sidewalk slab to thereby stabilize the saw, and accordingly cannot be used for precisely removing a raised portion of the sidewalk slab in a controlled fashion.
Having regard to the foregoing, there still exists a need for an improved masonry cutter.